Process for the manufacture of secondary amyl alcohol



.- Jan. l27, 1931. H. s. DAvls E'r AL v 1,790,523.

I PROCESS PQR THE, MANUFACTURE OF SEONDARY AMYL ALCOHOL original FiledFeb. 24, 1925 aww/14,420@

Paiemed- Jan. 27,"1931 UNITED STATES PATENT OFFICE f HAROLD S. DAVIS, OFBELMONT, AND WALDACE J'. MURRAY, 0F BEADm'G, MASSA- CHUSETTS, ASSIGNORS,BY MESNE ASSIGNMENTS, TO PETROLEUM CHEMICAL COR- PORATION, OF NEW YORK,N. Y., A CORPORATION OF DELAWARE Pnocnss Fon 'man MANUFACTUEE orSECONDARY Amr. ALCOHOL A Original application med February 24, 1925,Serial No. 10,992, and in Germany February 23, 1926.

Divided and this application filed March 28, 1930. Serial No. 439,654.

The olene mixtures produced by heating? such substances to temperaturesresulting in pyrogenetic transformations are, as is well known,exceedingly complex, generally containing ethylene, propylene,butylenes, amylenes, hexylenes and higherA oleines of thev generalformula CDHW Unlike saturated hydrocarbons, olefines arecapable ofreadily reacting or combining with reagents, includingthe polybasicacids. (of which sulphuric acid or phosphoric acid are typical) thehalogens and halogen compounds, hypochlorous and other acids.'

The reaction of sulphuric acid with the olefines has been known sinceits discovery in Faradays laboratory in 1826, and alcohols' have beenprepared from alkyl sulphuric acid products of this reaction on certainolefines by hydrolysis and distillation by numerous investigators sinceBerthelots research in 1863. Derivatives of olefines have been made on acommercial scale in this country by first preparing an acid reactiveliquor of sulphuric acid with oil gas since as early as'1906 (AmericanEther Company of Richmond, Virginia; P. Fritzsche, Zeitschrift furangewandte Chemie, 1896,- pp. 456, 45.9;- Die Chemische i fIndustrie,vol. 35, p. 637, 1912). Gases produced in the liquid phase cracking ofpetroleum have been similarly treated for the recovery of alcoholicmixtures including isopropyl,isecondary butyl and amyl alcohols. Thesetreatments, so far as we are aware, have been of a kind adapted to theincidental recoveryat gas works or petroleum pressure stills of gasesfrom cracking o erations rarely containing more than 12% o olenes andfree from any substantial contents of very reactive highly crackedhydrocarbons such as the diolenes. When any attempt has been made toproduce industrially from -mixed olefine bearing gases, such as thewaste gases from liquid phase cracking, acid reactive liquors capable ofhydrolysis and distillation to obtain alcohols, sulphation has beencarried out, so far as we are aware, by reaction upon the whole gaseousmixture with acid o a degree of concentration selected to reach a resultnecessarily in the nature of a compromise betweendes'truction bypolymerization or otherwise of the more reactive olefines, andincomplete sulphation; and hence, with partial recovery only of therealizable olefine values and with high acid consumption. Such processesare economically justiiiableonly when lean gases are available in greatquantities otherwise wasted. They are not so justiiiable when the gas tobe treated is rich in olelnes so reactive as to be converted intopolymers while making the olene-acid compound of a less reactiveremainder. When the olene bearing gas is rich in highly reactiveolefines, a single-sta e treatment to obtain acid products cannotpractised; the reaction of' the more highly reactive olefines and otherhydrocarbons to polymer under treatment with acids capable of ormingaddition `compounds with the less vreactive olefmes is too vigorous andtoo productive of heat to permit this even in the case of relativelylean gases.

The known procedure has therefore been to destroy the very reactableolefmes in vone lot of acid, and sulphate the remainder in' Aanother lotof acid.

If it were practicable toobtain mixed alkyl acid compounds and otherderivatives of the rich gases, such as result from vapor hase crackingdirected to the production o olefines, by a grou reaction with acid, theresult would'not desirable. The different alcohols, at least eight innumber, resulting from hydrolysis of t e obtainable compounds haveboiling points ranging from 80 to 140 C., and separation from each otheris in most cases not feasible. The uses of these alcohols (e. g.isopropyl and amyl alcohols) are widely diver ent, and to produce themin admixture would be commercially undesirable.

This process provides a treatment of oleine hydrocarbons, liquid orgaseous, articularly mixed hydrocarbons resulting rom as completegeneration of these substances as possible from asuitable hydrocarbonmaterial or carboniferous material of the classes above enumerated, andtherefore This new process thus provides a mode of treatment applicableto hydrocarbon products 'rich in highly reactive or unsaturatedvoleiines to recover valuable derivatives and segregate the olefinesubstances in the order of their chemical activities toward reagentsubstances, for example polybasic acids; and which will rmit theseparation production, severallrye or in groups, of olefine compounds,such as the olefine-acid compounds capable of hydrolysis or otherafter-treatment and se aration, leading to separate roduction o theconsequent different alcools or other olene derivatives. An objectattained by the process is the separation of complex olefine mixtures,especial y mixtures rich in defines, into fractions substantiallyaccording to the order ofv the molecular weights of their princi alcontents, and the treatment severally'of t ese fractions for the optimumproduction of valuable derivatives, e. g. the appropriate alcohols, in arelatively pure and unmixed'state; and without substantial destructionat any stage of this separation of any of the several fractions at therespective stage of the operations.

The process conserves for use at a further sta e of the process such ofthe reactive olenes as are not concerned a-t any stage of the process inthe reaction contrived and intended to produce a particular derivativeor intermediate. The recommended procedure comprises a stage or stagesof separation of a fraction or fractionsof thematerial containin theolefine or olefine groups to be 'recovere followed by treatmentselectively to differentiate and segregate the component oleinesubstances in accordance with their respective and relative chemicalreactivities. In general it may be stated that the preferred rawmaterial contains more than 30% of unsaturated hydrocarbons.

It is advantageous, in the practice of this process, to proceed upon abasis of known contents of the raw material, and for this purpose apreferred raw material for the process is petroleum, treated by anyprocess of vapor phase cracking tending to produce a product rich inolefines and preferably substantially free from normally liquid paraihnederivatives. A suitable and preferred raw material is the constant andcontrollable mixture produced by the process described in theapplication for Letters Patent by Earl P. Stevenson and Clarence K.Reiman, Serial No. 8907, filed February 13, 1925, which comprisessubjecting vapors of a petroleum or a fractional distillate ofpetroleum, for example gas oil, so called, to heat during flow in atubular retort heated at successive zones thereof to differing degrees,with the effect of maintaining the vapors at a nearly constant crackingtemperature during a substantial time of iiow, this constant temperaturebeing such as to result in optimum development of oleine values. Forthis purpose= a cracking temperature maintained nearly constant at aselected value between 600 C. and 650o C. during a sufiicient time offlow to produce from 1000 to 1700 cubic feet of gaseous product perbarrel of 42 gallons passed produces satisfactory material for thistreatment. The preferred vapor-phase cracking temperatures are higherthan those heretofore known for the commercial production of motorspirit, which do not exceed 500 C., so far as I am aware (Lewes, JournalSociety of Chemical Industry, Vol. XI, page 585) and are not such hightemperatures (7 00o to 1000 C.) as are used for making oil gas by theknown methods of Pintsch, F ritsche or Ullman.

The invention will therefore now be described as carried out upon thegaseous eillux vof vapor phase cracking of petroleum so contrived as toproduce a vaporous and gaseous eliux which, when stripped of amotorspirit fraction, is exceedingly rich4 in the olene substances abovementioned. But it will be understood that this process is applicablewithout change, except in degree, to the treatment of other complexolene mixtures, and that the `specific instances now to be described aredescribed by way of illustration of the invention, and are not to beviewed as comprising every instance of practice according to theinvention.

In the accompanying drawing, the figure is a diagrammatic flow sheetshowing a preferred assemblage of apparatus illustrative substantiallythe same boiling range as thcA e of certaih/ physical stages ofseparation of the material treated.

general, submitting theolefine-bearing gases to treatment` for thephysical separation of fractions. containin groups of olene substancescapable of c emical segregation cony comitantly with the formation ofoleine-acid compounds, emulsions, or solutions, under conditionspermitting the segregation severally of derivatives, for examplealcohols resulting from hydrolysis of these compounds. Y

Referring to the drawing, a container 1 for the supply of oil maydeliver to a feed stock reservoir 2, whence by a suitable pressuredevice 3 the material is forced into a preheater or primary vaporizer 4(preferably a suitable tubular coil) and through a superheater orsecondary stantiall'y t e same kind of tubular heater as the primarypreheater 4. Between the preheater 4 and superheater 6 the flowingstream, already substantially all vapor, may be sub )ectedY to treatmentadapted to separate out the inclusions of low volatility, and pass onthe vapors and gases. A liquid separator', preferably of a kindoperating without substantial loss of heat, is recommended. Col-i lectedliquids from this separator may How through a pipe 6l and a cooler C totar storage tanks 10.

Vapors superheated at 6 pass to a cracking tube 7. The eiiluent'gases,vapors and suspensions from cracking are recommended to be treated in aseparator 8, which may work on the cyclonic or centrifugal principle,and deliver its liquid separates into the pipe 6a, and its vaporous andgaseous eiilux into the bottom of the first of a series of separatingand .condensing towers, for example, the

tower 11, adapted to counter-current flow in contact of the vapors andgases and the condensate from tower 12, which in turn adapted tocounterfcurrent flow of the vapors and gases and the condensate from afractionating condenser 13 of Vany suitable redux' type.

The tower 12 isY preferably a fractionating tower of the bubble type.From the bottom is taken a relatively heavy fraction which is deliveredinto the top of tower 11,.where in it serves to condense and wash outany heavy and undesirable tars formed in the cracking reaction. From oneof. the lower plates of this tower is drawn voil? a fraction of feedstock, but as this will, df necessity, contain some hydrocarbons in themotor spirit range, it cannot be returned to the feed stock withoutmaterially decreasing the yield Aof motor spirit. Provision is included,therefore, for stripping this fraction of its lighter hydrocarbons, suchas a fractionating tower 1,2,.which is heated at the base at 14 anddelivers overhead the desired fraction of its vaporizer 6, which may besubfeed into one of the top plates of tower 12.

v The stripped cycle stock is delivered through The process to bedescribed comprises, in f a pipe 14 andcooler C to the feed stock tank.The overhead from 13 is cooled at 18, and the condensate at this pointis crude motor spirit inthe preferred o eration of tower 12.

The .vaporous e uent from condenser '18 is now fractionally condensed orabsorbed, or otherwise treated to separate olefine` fractions, whichfrom their\ preponderant contents, may be described as an amylenefraction, a butylene fraction, and a gaseous fraction rich in propyleneand ethylene, and hereinafter `referred to as a pro ylene fraction. Forexample,the gaseous e uent from condenser 18 may be delivered throughmeter,

M and scrubbed in absorption towers and 21 by a counter-current flow ofcool absorption oil stored in tank 23, delivered by a pump P1 through acooler C2 and pipe'24 to the top of tower 21, to receiver 25, pum ed atP2, through a cooler Ca to the top o tower 20,

and the saturated oil delivered through a pipe 26 to-a storage tank 27,whence the saturatedoil may flow through a heat exchanger 28, pipe still29 and vaporizer 30 to a refluxing tower 31, from which the liquids maybe led through cooler C4 to the crude motorspirit or gasoline storagetank 16 by pipe 32. Unvaporized absorption oil from vaporizer -30 mayflow through pipe 30, heat exchanger 28, and cooler C5 to tank 23.

The vaporous effluent at 33'may be delivered through a condenser 34 anda separator 35, whence the vapors pass to a com ressor 36'and pressurestorage tank 37. ondensates at 34, and 37 may be delivered to tank 17,thepressure andtemperatures being such as to provide at thesepoints-liquid fractions corresponding to the amylene-fraction fluid intank 17. Pressure tank 37 may deliver, if desired, through a suitablereduction valve 39 to gas-holder 40, in which are collected the residualgases from the saturated scrubbing oil. This gaseous fraction, if soseparated,

being separated by'steps of condensation orl absorption are sharplycharacterized bythe desired preponderance (amounting under goodconditions toy substantial freedom from -mixture with each other) of theolefine substances sought to be collected and separated. Any v suitablecondensation or absorption fractionating treatment may therefore beresorted to, and the apparatus mentionedv may be Avaried in accordancewith engineering preferences. v

"les

into comparatively simple fractions shows the relative amounts involvedand the quantity df each fraction:

Results of .S2-hour run (quantities per bbl. throne out) Gas oil used,31 Baume.

1 2. Crude motor-spirit recovered 74. 5 lbs 8. Cycle stock 110 lbs. 4i.Fuel oil B0 lbs. 5. Process gas at M (rich gas) 80 lbs. (1040 cn. ft.)0. Residual gas from compression to 250 pounds per sq. in 33.4 lbs. (583cu. ft.) 7. Pressure condensate 40. 61 lbs.

Products from pressure condensate 8. Amyiene fraction (liquid) (a) up to25 C 51 lbs (t) 245 C 5.15 lbs. 9. Butglene fraction(gaseous) 19.6 lbs.(181 cu. ft.) 10. Lig t naphtha (included ln 2) 11.35 lbs.

rliese .results are from separation by compression, (distillation andcondensation. When the absorption step, as described above, is resortedto,"typical results are as lfollows: Feed s'toc--,32'34 B. gas oil (fromsouth rlexas crude).

Feed rate-1 bbl. cracking tube.

Temperatures-#- per hour per six inch Vaporizer, 632 C. maximum. Tube,-601o C. (average).

i Tube sections (averages) Entrance 2 3 4 5 6 595 C. 602 C. 602 C'. 603C. 606 C. 603V C.

Conversions per bbl. passed Process gas (sp. gr. 1.055) 1035 cu. ft. Oilscrubbed gus (sp. gr. 0.929) 075 cu. It. Butylene fraction(non-condensed gus from distillation ot saturated absorption oils) (sp.gr.- 102 cu. ft. Amy ene fraction (condensables recovered byfractionation to C.) 2. 6 gallons Crude nnghthn (condensables between 60and 21 C. 9. 3 gallons Cycle stock (condensables above 210 C.) 19gallons Tar residues 2. 1 gallons Olelne content of gaseous fractionsProcess -frasi per cent oienes above ethylene 33. 1 Oil scrubbed gas percent oleilnes above ethylene 17. 8 Butylene fraction per cent olen aboveethylene 75. 7

Vapor phase cracking of the preferred practice having been carried on atthe temase cracking process above peratures mentioned, the products arechiefly unsaturated, being largely oleiines with some naphthenes andaromatic hydrocarbons, to gether. with almost negligible amounts ofsaturated or parailin hydrocarbons, particu- .larly in the lighterliquid fractions.l .The olefine content of the gas prior to compressingor oil scrubbing toremove condensables may be as highy as 54% by volumein the operation of an appropriate vapor phase cracking process, forexample that described. For comfor which other procedures may of coursebe substituted within lthe vinvention so long as the results areproduced, result in a fractionation of the oleines as follows:

Boiling ponts= Ethylene -103 C Propylene 48. 4 C Gnseous Iso-butylene -6C. Butylenes Butene-l C. Balcone-2 +1 C. Isopropyl ethylene 21 C. Unsym.methyl-ethyl-ethy- 31 g C ne -33 Liquid Amylenes Pentene-2 Trimethylethylene 37 to 42 C Pentene-l 39 to 40 C Hexylenes 55 to 75 C Higherolenes, up to C Associated with the amylenes and butylenes aresubstantial inclusions of diolefines, believed to be butadiene,isoprene, and their homologues.

We are aware of no practical arrangement of conditions or procession ofreagent substances by Which any Whole mixture of these gaseoussubstances can be treated to yield in succession the derivatives of theunsaturated hydrocarbons present in them in amounts constitutingvaluable sources of materials needed for industrial uses. But We havenevertheless determined that the substances are rellU active with thepolybasic acids, for example sulphuric acid, 1n a certain order,ethylene such as -propylene being the least reactive as follows: v

' -absorption of the lighter and simpler olenes or a quantitative ideaof the great variations in reactivity 1 Bonham am 1. Ethylene CILe-CH,103 C. Gas ,2, Propylene oH,-`cH=cH, #48.5 o.A ons 3. Pentene-lCH.CHCH,j-CH=CH2 39-40 C. v Liquid 4, remue-2 `cinoH2-c1a='oH-GH. 6 c.(741mm.) Liquid '5'. Beane-1 oH.-cH,-oH=oH, 5 c. Gas or in' solution 6.Butene2 CHr-'CH-CH-(JH, +1 C. Gas or in c I s ,solution- 7. I ro lahIene CH C 21.1c. Li uid p py y H-oH=oH, q

. QH, 8. Uns etrical methyll ethyl CH Y v31 to33C'.

' ethylene g Liquid CHr-CH 9. Trimeth lah len@v f cH H y y. a37m42w.Liquid 10. Iso-butyle e CH Y il I C=CHi 6C. Gras or in g solution. l Toabsorb ethyleiie and produce ethyl suled by'these oleiines towards sulhuric acid phurie acid it is necessary to use hot concenisobutylene isseveral hundre trated acid which will substantially poly# merize allother olefines above propylene 1n re` activity; the propylene will alsobe polymerized. I

With acid below 30 C., there is no appreciable absorption of ethyleneand the a sorption of propylene is'very ra id, but

"the yield of isopropyl alcohol will e small due to the excessivepolymerization ,when and if the gas treated contains the more reactiveolefines in the amounts in which they naturally occur.

The following causes may be responsible for this phenomenon:

(l.) The reactive 'olefines evolve so much heat on contact with thesulphuric acid that local overheatin occurs which tends to polymerizeall the lssolved products including propylene.

(2) The reactive oleiines combine with the sulphuric acid more rapidlythan propylene and decrease the ability of the acid to absorb thelatter.

(3) 100% sulphuric acid can easily act as an oxidizing agent toward thereactive olefines and the water evolved dilutes the acid and lowers itspower to absorb olefines.

Per contra, if the gas is' treated with acid of a 'strength adapted toabsorb trimethyl ethylene and ofthe proper strength and under 'theoptimum conditions to absorb the olefines which yield tertiaryderivatives (Nos- 8, 9, 10 above) there is no substantial times asreactive as ethylene.

In the case of isollilropyl ethylene, which so far as we are aware asnever, previous to the research leadin to this invention, been convertedinto an a cohol through reaction with sulphuric acid, acids of suicientstrength to absorb pentene-l'and pentene`2 quantitatively polymerize isoropyl ethylene at -temperatures below 30"v Cp her temperatures and moreconcentrated aci than this are uired to absorbthe other olefines for theres ts desired, and the conditions for securing a good yield of amylalcoholv from this particular olefine substantiall polymerize the otherolefines except ethy ene and propylene present in this mixed gas.

thousand By the fractionating procedure above described we have avoidedany necessity to subject to sulfpuhliuric acid absorption all of thereactive ole es at once, and any necessity for producing alcoholsincapable of being subsetlglently separated.

y processes extending'and developing the a mixture would be of little orno commercial value. As a specific example of this diiculty two pairs ofalcohols that cannot be separated by fractional distillation are:

Isopro yl alcohol (constant boiling mixture) oi ing oint 80.4 C.

Tertiary utyl alcohol-boiling point 79.92 C.

ticed where tertiary derivatives are not recovered. The usual procedureis to moderata,

ly dilute the roduct from sulphuric acid absorption wit water and then,distill. The

point to which this dilution must be ,carried to avoid destruction bythe action of the sul phuric acid on the alcohols during distillationvaries with thediierent alcohols but in the case of secondary alcoholsthere is little hazard in distilling from acid solution.

Tertiary alcohols, however, behave quite differently and tertiary amyllalcohol, for example, cannot safely be distilled from even a fso ,oneper cent solution without substantial decomposition. The preferredprocedure for recoverin tertiary alcohols from, admixture with sul uricac1d is to neutralize as with lime an distill from a neutral solution,It will be obvious that this procedure is not practical when applied toa complex sulphuric acid product containing small percentages oftertiary bodies as compared to secondar bodies. It becomes practical andfeasib e when the tertiary bodies are concentrated vand segregated as inthe practice of this invention.

The procedure above described, to avoid the diiiiculties and provide theadvantages just adverted to, separates the material into groups capableof being reacted upon preferentially in respect to their constituentmembers, thus enabling'separations of the acid combinations with theconstituent members of these groups severally. So far as there isadvantage in separating them,v these groups are:

(1) The gaseous fraction ethylene and propylene.

' (2) The butylene fraction containing isobutene and butene-l orbutene2or both of the initial low-boiling distillate fraction, and

(3) The residue of the condensate which containing may contain each ofthe five isomeric amyl-A Because this fraction will contain traces ofdioleines and olefines more reactlve than propylene, owing to the,practical and obvious limitation of any s stem for physicalfractionation, it is desira le to treat this fraction first with sulhuric acid, by tower scrubbing, of a strengt that will selectively reactupon the olefines (more reactive than ypropylene) therein present. Inthe preferred procedure this fraction is first scrubbed with acid of80-8470 strength and is then subjected to the act-ion of sulphuric acidhaving a concentration from 95 to 100% at' a temperaturepreferablyvbelow 30 C., whereupon propylene is substantially absorbed.AThe ethylene remains relatively unaffected and may be preserved andused in the gaseous condition, or subse uently be reacted upon, as forexample by a sorption in hot sulphuric acid resulting in the forma# tionof ethyl sulphuric acid; or. treated in any known way to produce ether.Specific and preferred modes of treating fraction (1) for the recoveryof these values form no part of the present invention. l

Gaseous products belong to other series of hydrocarbons which may bepresent in minor quantities as impurities, either remain in the gaseousstate, as in the case of methane or ethane, or remain-unabsorbed-by theacid 0 treatments; or, as 1n the case of acetylenes,

are converted into heavy compounds readily separable from the remainder,as by fractional distillation. If present, such bodies are not found inimportant quantities, and the resulting polymer is a heavy oily comound,of relatively uniform characteristics. n practice with hydrocarbonmixtures obtained as herein described the proportional amounts both ofsuch extraneous gaseous products and of the heavy oily polymer resultingfrom acid treatment are relatively small.

Upon hydrolysis of the acid compounds severally obtained as described,under suitable conditions, as by the addition of water or steam, anddistilling at correspondinlg. temperatures, ethyl and isopropyl alcoho srespectively may be recovered in the distillates, leaving a residue ofsubstantially alcohol-free sulphuric acid.

The butylene fraction (2) capable of economic use contains butylenesdiiiicult to separate from each other by distillation. Of these butene-land `butene-2 are less reactive chemically than iso-butylene.Derivatives of butene-1 and butene-2 as a consequence of theintramolecular structure of these substances have a secondary 'molecularformation, whereas 'derivatives of iso-butylene have a tertiarystructure. This may flow from the structure of'iso-butylene, conceivedas a central carbon bond being a double bond. As for example, theaddition of water (H2O) ture:-

y Preferred procedures therefore comprise reacting upon the butylenefraction 1n the order of reactivity of these component suband secondaryderivatives.

For example, the butylene fraction containing isobutene, butene-I andbutene-2 (all l' tert'a stances to form m severa Successmnl ry'.preponderantly of the amylenes and may con.--

gaseous) is passed through sulphuric acidof a concentration of 60% moreor less in `such manner as to effect as intimate a contact between thegas and the acid as possible, for the purpose of absorbing isobutene.Recommended apparatus comprises an interru ted flow tower with glass orother inert pac ing y arranged forfounter-current liow of gas and acid.Isobutene is very highly reactive; a

satisfactory differential absorption-is practicable at all ordinarytemperatures. vThe i'sobutene is here selectively absorbed, leaY- ingthe butene-I and butene-2 and other gases,

if any, which lare then conducted-through sulphuric acid of aconcentration of 80%,

more or less, by which the butene-l and butene-2-are substantiallyabsorbed. `Oneof the advantages of this procedure arises from havingremoved the substances ,reacting to V tertiary compounds, since thereaction of the secondary-alcohol-Yforming substances with strongerlacid for their conversion evolves heat of lesser degree, andthe naturalrise lof temperature, for example to 40 C., may be permitted to takeplace, unless acid more con centrated than 80% is resorted to, in'whichcase it may be desirable to. hold the ltemperature down to a point below15 C. 'These reactions are preferably carried out in a tower similal Vtothe towerjust mentioned; Aone ltower may be'used if arrangement is madeto collect the gaseous eillux and repass it, supplying the moreconcentrated acid on the second passage and separately collecting theliquid elux from the first and the second passage. i

The liquid from the first of said kSteps contains the isobutene eitherabsorbed in the acid or in the form of tertiary butyl alcohol byauto-hydrolysis in the dilute acid; this may be further diluted forcomplete hydrolysis and the alcohol distilled therefrom. Preferably thedilute liquid is neutralized with an alkali before distillation, toresult in a much higher yieldof the tertiary butyl alcohol byavoidanceof reaction with the acid' during C distillation.

The liquid from the secondl step of. treatment contains the butene-l andbutene-Q, and this liquid may be diluted for complete hydrolysis intothe secondary butyl alcohol, `65 and thereafter distilled withoutneutralizaaan momia a high'yield of secondary butyl alcohol.l Thedistillate maybe dehydrated, ifl desired, by any usual or customarywaterabsorbent chemical treatment, such as treat-v v ment with lime orcaustic. Y

The amylene fraction (3) whethercollected by absorption as described orb pressure con- -densation and Vfractional disti ation of fraction (l)(propylene, ethylene, etc.) consists tain hexylenes and higher olefinesas well a hydrocarbons of the group CnHfM. This liquid mixture, whichtypically contains less than 5% of paraliins, may advantageously be`distilled into three parts corresponding to temperatures l (a) Up to C.b) 25 to 45 C. (c) Above C.

' with sulphuric acid in stages, or the fractions (a) and (b) can beprocesses separately and with some advantage.

Distillate (a) contains predominant quantities of isopropyl ethylene.The specific treatment of this distillate forms no part of our inventionhereinclaimed.

In order to secure substantial yields of all alcohols derivativefrom`the mixed amylenes of fraction (b)- it is desirable to remove thehydrocarbons of the group Cnl-Im.2 (and any still less saturatedhydrocarbons) which may be present. Either alternative processes issatisfactory at this stage.

It'has beenk found, for example, that by treatin this fraction firstwith concentrated hydroc loric acid, the amylenes which are convertibleinto tertiary derivatives are substantially vconverted into chlorideswhich,

owing to their relatively high boiling points, can be easily separatedfrom the unchanged amylenes.

ethylene, unsymmetrical methyl-ethyl-ethylene and probably 'some of thehigher ole- The resulting mixture of` chlorides on hydrolysis, carriedon preferably fines while concurrently effecting the polymerization ofdiolel'ines and those hydrocarbons of a lesser degree of saturation thanthe oleines into heavy, oil-like polymers which, on account of diversityo boiling points, may be separated by fractional distillation, or otherappropriate means, from the unchanged olefines.

As the result of this preliminary reaction,

1d for example either the said hydrochloric or sulphuric acidtreatments, a highly refined am lene fraction remains after treatment,whlch fraction is substantially a mixture of isopropyl ethylene,pentene-l and pentene-2, and which does not contain appreciable amountsof the other olefines, though there is no disadvantage in the presenceof substantial'amounts of 'the normal butylenes and hexylenes at thisstage, since these olefnes are of the same order of activity as theamylenes therein present, and their derivatives can easily be separatedfrom those of the amylenes by fractional distillation.

Addition of sulphuric acid of a concentration of 77% more or less tothis refined amylene causes absorption with concurrent formation of thecorrespondin intermediates of the alcohols from whic the correspondingalcohols may be recovered by dilution and distillation.

Tofurther illustrate the advantage of this invention we have treated therich gas from vapor phase cracking as described, without first removingthe amylene fraction, with 95% acid. The result was an evolution ofexcessive heat, rendering control dif,- icult, if not imposslble, andthe recovery of small amounts only of secondar alcohols, and no tertiaryl alcohols. here were also formed'l large uantities of heavy tar-likepolymers, By rst removing l the olefines higher than propylene we havesuccessfully used fuming sulphuric acid as an absorbent for theremainder, obtained an alcohol yield of 40% of the weight of acid used,and'minimized the polymer formation to under of the alcohol 'produced.

For specific examples of treatment of the amylene fraction 3, (b) Wehave obtained the following results:

Example I From the processing of 32 B. gas oil under the conditionsmentioned for example above, there is obtained 2.6 gallons of amylenefraction (condensables 'recovered by 'fractionation to 60 C.) 'perbarrel passed.

hoursV as a maximum, adding the acid in two equalportions -at 3 hourintervals. At the end of this period agitation is stopped and themixture allowed to settle for a 'time suflicient to result in separationinto two welldefined layers. We first draw olf -thelower or acid layer,which is carefully neutralized with caustic and distilled, preferablythrough a fractionating column, cutting when the tempera'ure reaches 100C. at the top of the column. Under these specific conditions werecovered in this example .28 gallons of crude tertiary alcohols per 2.6gallons of amylene fraction treated.

The residual hydrocarbons from this treatment to recover tertiaryalcohols are distilled through a fractionating column from a slightlyalkaline mixture, andthe distillate up to C. is segregated and treatedfor conversion into secondary alcohols.

Starting with 2.6 gallons of amylene fraction, there is recovered 1.1allons of hydrocarbons boiling up to 60 which are now 'treated with 77%HQSO.1 in two portions, each of .55 gallons or 7.65 lbs. In this stagethe temperature is allowed to rise to 35 C.I and maintained at under 40C. preferably, and agitation isV continued over a total period of sixhours. The mixture is then allowed to settle and the lower or acid layeris drawn off, diluted with water to bring the concentration of acidbelow 20%, and then distilled until practically all of the alcohol iscarried over. The distillate consists of two layers, a lower or waterlayer and an upper or alcohol layer. From the 2.6 gallons of amylenefraction at the start of thls processing, there is recovered under theabove speciic conditions .56 gallons of crude secondary alcohols. Y'

Secondary and tertiary butyl alcohols 'are successfully recovered fromthe butylene fraction -by first scrubbing with more or less sulphuricacid, and then with 77% more or less' sulphuric acid, as abovedescribed.

-ExampleV II Concurrently with the production of 2.6 gallons of amylenefraction there isV recovered 102 cu. ft.4 of butylene fraction as setforth in the example above of a typical vapor phase cracking operation.As stated, this fraction can be a sobed under pressure or by cooling orboth in the amylene fraction; or it can be treated separately to producetertiary and secondary butyl alcohols. The following is an example ofseparate treatment: A A

The butylene fraction is first scrubbed or treated with a relativelydilute sulphuric acid, followed by more concentrated acid. We haveobtained satisfactory results by using in the first absorption stage 65%acid and 1n the second 77% acid. The amount of lllO acid requireddepends upon the physical eiliciency of the absorption a/pparatusemployed in large measure; using even/comparatively' inetlicientapparatus, an acid efficiency can be realized wherein three'pounds ofacid (calculated as 93%) produces one pound of alcohol. From thetreatment of 100 cu. ft. of the butylene fraction herein described, wehave produced .28 gallons of tertiary and .46 gallons of secondaryalcohols.-v

During the absorption of the butylene in the treatment for tertiaryalcohol with the particular reagentsA mentioned above we prefer to keepthe temperature below 20 C., and during the secondary stage at about 35C. As lin the case ofythe tertiary amyl alcohol, it is necessarytodistill the tertiaryA butyl alcoholl from a neutral or slightly alkaline.solution to secure the highest yields, though tertiary butyl is notsubject to decomposition in acid distillation in the same degree astertiary amyl alcohol.

lVherever in this specification particular concentrations ot' acidreagent substances adapted to olefine absorption are alluded to, it willbe understood according to the common knowledge of the numerous chemistsfamiliar with the behavior of acids toward olefines for nearly'acentury, that the acld concentration is relative to the respectively imentioned or to normal temperatures, and that at diierent temperaturesanother concentration of acid is equivalent, within those limits atwhich the action of the a'cid reagent ceases to become an absorption,and enters upon-the destructive formation of the' compounds hereinalluded to as polymers.

For the operations of fractional treatment with ILS()4 e. g. of theamylene fractiom (b) we recommend the use of apparatus com: prising'achamber adapted to be heated or cooled, and equipped for mechanicalagitation of its contents; adapted for the slow feed of acid of theappropriate concentration; suitable settling vessels for decanting oli"the unchanged residue of the materials of lesser reactivity; andappropriate vessels for acid reaction upon the decanted residue.,

Distillation of the olefine-acid liquors may proceed in appropriatesteam stills. In 'essentials, the units of apparatus required arefamiliar in the practice of the chemical industries, and one of theadvantages of this invention resides in the relatively simple nature ofthe instruments and'operations required. f

We claim:

l. In the process of generating secondary amyl alcohol from a mixture ofhyrocarbons produced by cracking petroleum oil and containing olefines,the steps of separating from moving tertiary oleines from said fraction,and thereafter sulphating the secondary olenes contained in saidfraction by adlnixing said fraction with aqueous sulphuric acid whilemaintaining an acid concentration and a temperature at which sulphationof said.

secondary olefines takes place.v

2. Process according to claim 1, in which the selective removal oftertiary olelines from said `fraction is accomplished by admixing saidfraction with aqueous sulphuric acid of from to 65%, H'gSO, content,while maintaining a temperature below that at which substantial amountsof said secondary olenes are suIphated.

3. Process according to claim 1, in which the selective removal oftertiary olefines from said fraction is accomplished by admixing saidfraction with aqueous sulphuric acid of from 60 to 65%., 'H2SO4 content,at tem-v peratures not exceeding 20 C.

4. In the process of 'generating secondaryamyl alcohol from a mixture ofhydrocarbons produced by cracking petroleum oil andcontaining not lessthan '30% of olefines, the steps of separating from said mixture. bydistillation a fraction, the oleine content of whichl consistspredominantly of secondary' and tertiary olelines of 5 carbon atoms tothe molecule, selectively removing tertiary olefines from said:fraction` and thereafter sulphating the secondary olel'ines containedin said fraction by admixing said fraction with aqueous sulphuric acidWhile maintaining an acid concentration and a temperature at whichsulphation of said secondary olefines takesplace.

5. vProcess according to claim 4, in which di' theselective removal oftertiary-olefines from said fraction is accomplished by admixing saidfraction with aqueous sulphuric acid of from 60 to 65%, HSO, content,while maintaining a temperature below that at which substantial amountsof said secondary olefines are sulphated.

6. Process according to claim 4, in which the selective removal oftertiary olenes from said fraction is accomplished by admixing saidfraction with a ueous sulphu'ric acid of 'from 60 to 65%. I -I2 O4content, at tempera,

tures not exceeding 20 C. t

' l HAROLD S. DAVIS.

WALLACE J. MURRAY.

said mixture by distillation a fraction, the

